Consider the equilibrium reaction: 3CIO-(aq) ↔ CIO3-(aq) + 2CI-(aq) The equilibrium constant Kc = 3.2 x 103. The following concentrations are present: [Cl-] = 0.50 mol/L; [ClO3-] = 0.32 mol/L; [ClO-] = 0.24 mol/L. Is the mixture at equilibrium and, if not, in which direction will reaction proceed?

The reaction quotient of an equilibrium reaction measures relative amounts of the products and the reactants present during the course of the reaction at particular point in the time.

Q < Kc , reaction will proceed in forward direction.

Q > Kc , reaction will proceed in backward direction.

Q = Kc , reaction at equilibrium.

It is the ratio of the concentration of the products and the reactants each raised to their stoichiometric coefficients. The concentration of the liquid and the gaseous species does not change and thus is not written in the expression.

Thus, for the reaction:

[tex]3CIO^{-}_{(aq)}\rightleftharpoons CIO_3^{-}_{(aq)}+2Cl^{-}[/tex]

The expression is:

[tex]Q=\frac {[CIO_3^{-}][Cl^{-}]^2}{[CIO^{-}]^3}[/tex]

Given,

[Cl⁻] = 0.50 mol/L; [ClO₃⁻] = 0.32 mol/L; [ClO⁻] = 0.24 mol/L

So,

[tex]Q=\frac{0.32\times (0.50)^2}{(0.24)^3}[/tex]

Q = 5.7870

Since, Q < Kc ([tex]3.2\times 10^3[/tex])

The reaction will go in forward direction.